|Morgan, Thomas - Tom|
Submitted to: Bioscience Biotechnology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/28/2005
Publication Date: 5/15/2005
Citation: Yoza, K., Imamura, T., Kramer, K.J., Morgan, T.D., Yaguchi, M., Nakamura, S., Kawasaki, S., Takaiwa, F., Ohtsubo, K., Beeman, R.W. 2005. Avidin expressed in transgenic rice confers resistance to the stored-product insect pests, Tribolium confusum and Sitotroga cerealella. Bioscience Biotechnology and Biochemistry 69:966-971. Interpretive Summary: Insects damage rice in storage, and conventional control techniques, such as fumigants or residual insecticides, are being lost due to registration or resistance problems; thus, alternatives to these conventional control techniques are required. One alternative technology is use of transgenic rice varieties that have resistance to insects. We showed that transgenic rice that contains avidin, a protein that binds the vitamin biotin, is resistant to two of the major insect pests of rice, and that the avidin breaks down by heating to 95 degrees C., suggesting that cooking the rice would break down the avidin. The results indicate that the use of avidin rice would reduce pest damage in storage.
Technical Abstract: Rice (Oryza sativa var. Nipponbare) was transformed with an artificial avidin gene. The features of this construct are as follows: (1) a signal peptide sequence derived from barley alpha amylase was added at the N-terminal region, (2) codon usage of the gene was optimized for rice, and (3) the gene was driven by rice glutelin GluB-1, an endosperm-specific promoter. Avidin was produced in the grain of the transgenic rice but not in the leaves. The concentration of avidin in the kernels was about 1,800 ppm. All larvae of the confused flour beetle (Tribolium confusum) and Angoumois grain moth (Sitotroga cerealella) died when fed transgenic avidin rice powder or kernels, respectively, whereas most of the test insects developed into adults when they were fed a nontransgenic rice control diet. Avidin extracted from the transgenic rice kernel lost most biotin-binding activity after 5 minutes heating at 95 degrees C.